Sheet coating machine



March 29, 1938. w. w. MAHER 2,112,246

vSHEET COATING MACHINE Filed July 6, 1936 2 Sheets-Sheef` 1 Fig-.I 36,

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W. W. MAHER SHEET COATING MACHINE Filed July 6, 1936 2 Sheets-Sheet. 2

7V. ATTORNEY Psienied Mar. 29, 193s' PATENT OFFICE f I SHEET coATINGMACHINE William W. lMaher, San Francisco, Calif., as-

signor to American Can Company, ,New York, y N. Y., a corporation of NewJersey L Application July 6, 1936, Serial No. 89,195

9 Claims.

The present invention relates to printing presses or coating machines ofthe off-setprinting type which utilizes a rotatable impression cylinderfor applying a film or a design of coating material to a surface ofsheet stock such as, for example, tin plate or the like and hasparticular reference to creating and maintaining an exact and uniformfilm for printing orv coating by preventing piling up or unevenness orexcess accumulation of the coating material on the impression cylinder,such a desiderative being best' obtained by suitable mechanism for rstwiping off the impression cylinder as it rotates to insure a cleansurface for each application of such a iilm or design of coatingmaterial,

and vsecond for uniformly distributing and smoothing out the coating onthe cleaned surface preparatory to its transfer to the sheet.

An object of the invention is the provision of a coating machine whichutilizes a rotatable impression cylinder for applying coating material4to sheets to be coated wherein any residual coating material, which maybe left on the impression cylinder after an impression has been made orwhich may remain on the cylinder because no sheet was presented, ispicked up or wiped off before each application of. the film or design tothe impression cylinder.

Another object is the provision of such a coating machine wherein thecoating material applied to the cleaned surface of the impressioncylinder, as for example, by means of the usual transfer roller, isfurther uniformly distributed on the cylinder and is smoothed out evenlyover its surface, any coating material in excess of the required lm asit lies on the impression cylinder, being picked up and carried backonto the transfer roller so that a smooth and exact even lm of thedesired thickness will be applied to the sheet.

Numerous other objects and advantages of the invention will be apparentas it is better understood from the following description, which, takenin connection with the accompanying drawings, discloses a preferredembodiment thereof.

Referring to the drawings:

Figure 1 is a vertical cross-sectional view of an exemplary type ofcoating machine embody-l ing the instant injfention, parts of themachine being broken away;

. Flg. 2 is a horizontal section taken substantially along the brokenline 2-2 in Fig. 1, with parts removed; and

Fig. 3 is an enlarged perspective detail as viewed substantially fromaposition indicated by the line 3-3 in Fig.2, certain of the parts beingbroken back and shown in section while other parts are broken away.

As a preferred embodiment of the inventio the drawings illustrate theprincipal parts `of a,

conventional off-set printing or coating machine which is utilized inapplying a lm or design of coating material which may be varnish,lacquer, ink or the like, to the surface of a' sheet A.

Such a conventional machine comprises suitable side frames I I (Fig. 1)which support a pair of spaced and parallel, constantly rotatingcylinders including an impression cylinder I2 and a gripper cylinder I3between which is passed a sheet A to be coated.

The impression cylinder I2 is -mounted on a horizontal shaft I5 havingits ends journaled in suitable bearings formed in the side frames II.This cylinder carries the film or' design of coating material to beimpressed upon the sheet A. The cylinder is rotated in the directionindicated by the arrow in Fig. 1 by a driving gear I6 which is mountedon one end of the shaft I5 and which is driven in any suitable manner.

The gripper cylinder I3 is mounted on a horizcntal shaft I8 having itsends journaled in suitable bearings formed in the side frames II. Thiscylinder is rotated at the same surface speed as the impressioncylinder, the cylinders being geared together by spur gears 2|, 22 whichare mounted on the respective shafts I5, I8. The gripper cylinderpresses the sheet A into tangential contact with the impression cylinderthe while advancing the sheet horizontally between them.

The sheet A is fed into the grip of the cylinders I2, I3 from ahorizontal table 24 which is secured to the side frames II. 'I'he tablecarries a feeding device comprising a pair of spaced and parallel feedbars which are disposed in grooves 26 formed in the table and which arereciprocated through a forward and a return stroke by any suitable meansmoving in time with the other moving parts of the machine. Feed dogs 21which are carried on the feed bars engage behind the sheet during theforward stroke of the bars and push it into position for feeding.Passage of the sheet between the cylinders impresses the coatingmaterial thereon.

The coated sheet as it leaves the cylinders I2, I3 is supported on anendless belt conveyor 3| carried on a pair of pulleys 32 which aremounted on horizontal shafts 33. The shafts are journaled in suitablebearings formed in the side frames I I and are rotated by any suitablemeans operating in time with the other moving parts of the machine. Theconveyor deposits the coated sheets onto a discharge table 34 from whichthey may be removed as desired. The discharge table is secured to thesides frames II.

The coating material used in coating the sheet A may be supplied to themachine by a pipe 36' (Fig.v 1) from which it ilows as a continuousstream, indicated by the letter B, onto a pair of C Qntinuously rotatingrollers. These rollers run in surface contact as fountain rollers 36, 31the latter functioning as a transfer roller.

These rollers are carried on horizontal shafts 38, 39 having their endsjournaled in suitable bearings formed in the side frames Meshing gears4|, 42 (Fig. 2) carried on the ends of the shafts 38, 39 rotate therollers in unison in the direction of the arrows shown in Fig. 1 and atthe same surface speed as the impression cylinder. The gear 42 mesheswith and is driven by the gear 2|.

Transfer roller 31 engages with the impression cylinder |2 and transfersthe coating material received by it to the surface of the impressioncylinder. The coating material thus applied to the impression cylinder,is spread out or distributed over its `exterior surface by adistributing roller 45.

The distributing roller 45 is located adjacent the transfer roller 31 ontop of and engaging the impression cylinder I2. It is mounted on ahorizontal shaft 46 (Figs. l and 3) having its ends journaled in bearingblocks 41 which are carried in U-shaped recesses 48 formed in brackets49 which are secured to the side frames Il. The bearing blocks aresupported on springs 5|. Adjusting thumb screws 52 engaging the top ofthe blocks and carried in bosses 53 formed on the bracket are providedfor adjusting the pressure of the distributing roller against theimpression cylinder. A gear 54 mounted on the distributing roller shaft46 meshes with the impression cylinder gear 2| and rotates thedistributing roller at the same surface speed as the impressioncylinder.

Uneven distribution and excess of coating material on the usualimpression cylinder often results from the repeated applications thereonof the coating medium and sometimes causes undesirable streaks andblotches on the surface of the sheet A being coated. This condition isprevented in the present case by the use of a wiper roller 55 whichcleans the surface of the impression cylinder at each rotation cycle andby an auxiliary distributing roller 56 which more thoroughly distributesand smooths out the coating material which is applied to the impressioncylinder. It is these features to which the present invention isparticularly directed.

The wiper roller 55 is located below the transfer roller 31 and is inengagement with the impression cylinder. This wiper roller is mounted ona horizontal shaft 6| having its ends journaled in bearing blocks 62(Figs. 2 and 3) which are carried in slots 63 formed in brackets 64secured to the side frames 'I'he bearing blocks are held under springtension by means of springs 66 located in recesses 61 (Fig. 2) formed inthe brackets adjacent one end of each slot.

Thumb screws 68 threaded into the brackets at the opposite ends of theslots provide adjustment for holding the wiper roller against theimpression cylinder with the desired amount of pressure. A gear 1|mounted on the wiper roller shaft and meshing with the impressioncylinder driving gear 2| rotates the wiper roller at the same surfacespeed as the impression cylinder.'

The wiper roller picks up residual coating material which may be left onthe impression cylinder after a preceding impression has been made.Also, if no sheet is passed through the machine the lm of coatingmaterial remaining on the impression cylinder as a result of suchfailure of printing is entirely wiped oi by the wiper roller. In thismanner the impression cylinder.

is always cleaned off before a new lm of coating material is applied.Thus accumulation of repeated applications is prevented and streakingand blotching of printed sheets are avoided.

Coating material picked up by the wiper roller 55 is removed by ascraper blade 13 which bears against the wiper roller. The scraper bladeis held by a clamping plate 14 to an angle iron frame 15 which hasbearing blocks 16 secured to its ends. These blocks are formed withinverted U-shaped slots 11. Projecting ends of stationary shoulderedpins 18 carried'in the wiper rol1er.bearing blocks 62 t within the slots11 of the bearing blocks 16 and thus support the scraper frame.Adjusting set screws 19 threaded into the scraper frame and the bearingblocks 16 bear against the side of the projecting ends of the pins 18and hold the frame and scraper in adjusted position against the wiperroller.

The residual coating material picked up by the Wiper roller 55 is thusscraped off as it is collected. This coating material falls into ahopper 8| secured to the side frames and is discharged to a suitableplace of deposit by a pipe 82 one end of which is connected to thehopper.

The auxiliary distributing roller 56 is located between the transferroller 31 and the distributing roller 45 and frictionally engages bothof these rollers. It is mounted on a horizontal shaft 85 having its endsjournaled in bearing blocks 86 which are carried in inverted U-shapedrecesses 81 formed in the brackets 48 adjacent the U-shaped recesses 48.This roller picks up excess coating material from the distributingroller which has functioned to distribute the freshly applied coatingreceived on the cleaned surface of the impression roller by the transferroller, This excess is carried back by the auxiliary roller anddeposited onto the transfer roller for re-use. In this manner theauxiliary roller relieves the distributing roller of any excess materialpicked up by it from the impression cylinder and assists thedistributing roller to more uniformly spread out, in a smooth even lm ofdesired thickness, the coating material applied to the impressioncylinder.

It is thought that the invention and many of its attendant advantageswill be understood from the foregoing description, and it will beapparent that various changes may be made in the form, construction andarrangement of the parts without departing from the spirit and scope ofthe invention or sacrificing all of its material advantages, the formhereinbefore described being merely a preferred embodiment thereof.

I claim:

1. In a machine for coating sheets, the combination of an impressioncylinder for applying the coating material to a sheet, a transfer rollerengaging said impression cylinder, said transfer roller receiving thecoating material and depositing the same on the impression cylinder, adistributing roller also engaging the impression cylinder fordistributing the coating material thereon, and an auxiliary distributingroller disposed between and engaging the distributing roller and thetransfer roller for smoothing out the coating material on saidimpression cylinder and for carrying back to said transfer roller anyexcess material applied to said impression cylinder.

2. In a machine for coating sheets, the combination of an impressioncylinder for applying the coating material to a sheet, a transfer rollerengaging said impression cylinder, said transfer roller receiving thecoating material and depositingthe same on the impression cylinder, adistributing roller also engaging the impression cylinder fordistributing the coating material thereon, means for driving saidrollers and said cylinder at equal surface speed, and an auxillary.distributing roller engaging the distributing roller and the transferroller and driven by frictional contact therewith, for smoothing out thecoating material on said impression cylinder and for carrying back tosaid transfer roller any excess material applied to said impressioncylinder.

3. In a machine for coating sheets. the combination of an impressioncylinder for applying the coating material to a sheet, a grippercylinder disposed adjacent said impression cylinder for conveying asheet therebetween to effect the application of the coating material tothe sheet, feeding devices for presenting a sheet between saidcylinders, a plurality of contacting fountain rollers adapted to firstreceive the coating material, one of said rollers engaging saidimpression cylinder to transfer and deposit a film of the coatingmaterial on said impression cylinder, a distributing roller alsoengaging the impression cylinder for distributing the coating materialthereon, and an auxiliary distributing roller engaging the distributingroller andthe transferring roller for smoothing out the coating materialon said impression cylinder and for carrying back to said transferroller any excess material applied to said impression cylinder.

4. In a machine for coating sheets, the combination of an impressioncylinder for applying the coating material to a sheet, a transfer rollerengaging said impression cylinder, said transfer roller receiving thecoating material and depositing the same on the impression cylinder, awiper roller also engaging said impression cylinder for picking upresidual coating material left on said impression cylinder to preventits accumulation, and means interposed between said impression cylinderand said transfer roller for returning to the latter excess coatingmaterial deposited on said impression cylinder.

5. In a machine for coating sheets, the combination -of an impressioncylinder for applying the coating material to a sheet, a transfer rollery engaging said impression cylinder, said transfer \ro11er receiving thecoating material and depositing the same on the impression cylinder, anda wiper roller also engaging said impression cylinder for picking upresidual coating material left on said impression cylinder to preventits accumulatiom instrumentalities for removing said residual coatingmaterial from said wiper roll, and means interposed between saidimpression cylinder and said transfer roller for returning to the latterexcess coating material 4deposited on said'impression cylinder.

6. In a machine for coating sheets, the combination of lan impressioncylinder for applyingthe coating material to a sheet, a transferroller-engaging said impression cylinder, said transfer roller receivingthe coating material and' depositing the same on the impressioncylinder, a wiper rollei also engaging said impression cylinder forpicking up residual coating material left on said impression cylindertoprevent its accumulation, means driving said rollers and said cylinderat equ'alsurface speed. instrumentalities for removing said residualcoating material from said wiper roll, and means inter'- posed betweensaid impression cylinder and said transfer roller for returning to thelatter excess coating material deposited on said impression cylinder.

7. In a machine for coating sheets, the combination of an impressioncylinder for applying the Acoating material to a sheet, a grippercylinder disposed adjacent said impressio cylinder for conveying a sheetduring coating, eding devices for presenting the sheet to saidcylinders, a` transfer roller engaging said impression cylinder, saidtransfer roller receiving the coating material and depositing the sameon the impression cylinder, a wiper roller also engaging said impressioncylinder for picking up residual coating material left onthe latterafter an impression has been made or for picking up the coating materialleft on said cylinder when no sheet is fed for an impression, a scraperinstrumentality engaging the periphery of said wiper roller for removingtherefrom its collected residual coating material, and means interposedbetween said impression cylinder and said transfer roller for returningto the latter excess coating material deposited on saidimpressioncylinder.

8; In a machine for coatingsheets, the combination of an impressioncylinder for applying an impression of the coating material to a sheet,a transfer roller engaging said impression cylinder, said transferroller receiving the coating material and depositing the same on theimpression cylinder. a distributing roller also engaging the impresioncylinder for distributing the coating material thereon, an auxiliarydistributing roller engaging both the distributing roller and thetransfer roller for smoothing out the coating material on saidimpression cylinder and for carrying back to said transfer roller anyexcess material applied to said impression cylinder, and a wiper rolleralso engaging said impression cylinder for picking up residual coatingmaterial left on said impression cylinder after an impression has beenmade or for picking up the coating material on said cylinder when nosheet is presented to receive an impression.

9. In a machine for coating sheets, the combination of an impressioncylinder for applying an impression of the coating material to a sheet,a transfer roller engaging said impression cylinder, said transferroller receivinglthe coating material and depositing the same on theimpression cylinder, a distributing roller also engaging the impressioncylinder for distributing the coating material thereon, an auxiliaryldistributing roller engaging both the distributing roller and thetransfer roller for smoothing out the coating material on saidimpression cylinder and for carrying back to said transfer roller anyexcess material which was applied to said impression cylinder, a wiperroller also engaging said impression cylinder for picking up residualcoating .material left on said impression cylinder after an impressionhas been made and also for picking up the coating material on saidcylinder when no sheet is present to receive an impression, andinstrumentalities for removing from said wiper roller the coatingmaterial collected thereon.

